Optical fiber tip diffuser and method of making same

ABSTRACT

An optical fiber for use with a laser device including a source of light energy, as well as a method of making same, where the optical fiber has a proximal end in communication with the light source and a distal end positionable at a treatment site. The optical fiber includes: a core having a proximal portion, a distal portion and a distal face proximate the distal end of the optical fiber, a layer of cladding radially surrounding the core from the core proximal portion to a designated point adjacent the core distal portion; a sleeve radially surrounding the cladding layer composed essentially of a predetermined type of material; and, a tip diffuser positioned at the distal end of the optical fiber.

RELATED APPLICATIONS

This patent application cross references and incorporates by referencethe following co-pending, commonly assigned patent applications filed oneven date herewith: “OPTICAL FIBER FOR A LASER DEVICE HAVING AN IMPROVEDTIP DIFFUSER AND METHOD OF MAKING SAME”, attorney docket END 5216,U.S.Ser. No. ______ “OPTICAL FIBER FOR A LASER DEVICE HAVING AN IMPROVEDDIFFUSER SLUG AND METHOD OF MAKING SAME”, attorney docket END-5215, U.S.Ser. No. _______ .

BACKGROUND OF THE INVENTION

The present invention relates generally to an optical fiber for use witha laser device and, more particularly, to an optical fiber having animproved diffuser configuration at its distal end for performing thedual functions of scattering light and providing a temperature signal.

Currently, surgeons employ medical instruments which incorporate lasertechnology in the treatment of benign prostatic hyperplasia, alsocommonly referred to as BPH. BPH is a condition of an enlarged prostategland, where such gland having BPH typically increases in size by abouttwo to four times. The laser energy employed by the surgeons to treatthis condition is delivered by an optical fiber which must be able todistribute light radially in a predictable and controlled manner. Duringthe course of such treatments, one parameter of great importance is thetemperature of the tissue being treated. For example, one currentrecommendation for forming lesions in the prostate as a treatment forBPH is to heat a small volume of tissue to 85° C. for a designated timeperiod depending on fiber and laser design. It will be appreciated thatheating the tissue to a lesser temperature has the effect of incompletelesion formation, while heating the tissue to a higher temperature cancause excessive tissue damage. Accordingly, the ability to accuratelymeasure the temperature of the optical fiber tip during treatment is ofprimary concern.

It will be understood that there are several known ways of performingthe temperature monitoring function for a laser system. One approach hasbeen utilized in laser treatment systems known as the “Indigo 830eLaseroptic Treatment System” and the “Indigo Optima Laseroptic TreatmentSystem,” both of which are manufactured by Ethicon EndoSurgery, Inc. ofCincinnati, Ohio, the assignee of the present invention.

Methods of providing an optical fiber with a diffuser end are disclosedin U.S. Pat. No. 6,522,806 to James, IV et al., U.S. Pat. No. 6,361,530to Mersch, and U.S. Pat. No. 5,946,441 to Esch. Each of these methodsutilize the principle of relying upon the temperature dependence of thefluorescent response of a slug of material at the fiber tip to anoptical stimulus as described in U.S. Pat. Nos. 5,004,913 and 4,708,494to Kleinerman. More specifically, a pulse of pump energy causes afluorescence pulse in an alexandrite slug which is delayed by a timeinterval corresponding to a temperature of the material.

It will be appreciated from each of the aforementioned patents that theslug is composed of a cured mixture of alexandrite particles and anoptical adhesive which is cured in place. The current manufacture andassembly of such slugs is considered both complex and tedious. In anexemplary process, the slugs are formed in batches by sprinkling groundalexandrite into several tiny cavities in a mold placed on a vibratoryplate. The alexandrite particles are then covered with an opticalcoupling adhesive, after which a vacuum is drawn and the mixture iscured within the mold using either heat or ultraviolet light. The slugsare removed from the mold as a batch and placed individually into thedistal sleeve tip against the end of the fiber optic glass duringassembly.

While various improvements have been made in the basic slugmanufacturing process, they are all based on the slug being a mixture ofalexandrite and adhesive and therefore have similar disadvantages. Onedisadvantage is that a portion of the final molded configuration is usedas structural support, which results in substantial waste of theexpensive alexandrite material. The manufacturing process is consideredto be lengthy and requires the use of specialized equipment and highlytrained operators.

Moreover, the ratio of alexandrite to the ultraviolet binder (i.e., itsconcentration) in each individual cavity of the slug mold is notprecisely controlled, which results in a variation of the slugcomposition and its resulting performance. It will also be understoodthat assembly of the slug within the distal tip of the optical fiber isdifficult since the slug is unidirectional, the size of the componentsin the optical fiber is extremely small, direct visualization is notavailable, and neither mechanical positioning nor final mechanicalinterlock is provided between the components.

In an alternate variation of the current manufacturing process, anuncured mixture of alexandrite and adhesive may be directly applied tothe end of the fiber and cured into place. This may be accomplished bydispensing the mixture within the tubing directly onto the end of theglass core, loading it into a sleeve or other carrier and seating thesleeve, or by dipping the core end into adhesive and then into thealexandrite particles. It has been found in this process, however, thatapplication of a consistent amount of the mixture in the proper locationis difficult to achieve and monitor on a production basis.

Thus, in light of the foregoing, it would be desirable for a slug, aswell as a method of making and assembling such slug in an optical fiber,to be developed which overcomes the disadvantages associated with thealexandrite and adhesive composition and manufacturing processesdescribed herein. It is also desirable that such slug would assist incentering the slug on the distal surface of the optical fiber andassuring contact between the fiber core and an outer sleeve, whereby thedual functions of light scattering and temperature sensing areoptimized. Further, it is highly desirable for the light-scatteringmaterial and the sleeve of the diffuser portion for such optical fiberto be formed in an integral manner. In an alternative configuration, itwould be desirable for the separate slug to be eliminated from theoptical fiber and replaced with a tip diffuser having light scatteringand temperature sensing capabilities which can be assembled to thedistal end of the optical fiber.

BRIEF SUMMARY OF THE INVENTION

In a first exemplary embodiment of the invention, an optical fiber foruse with a laser device including a source of light energy is disclosed,where the optical fiber has a proximal end in communication with thelight source and a distal end positionable at a treatment site. Theoptical fiber includes: a core having a proximal portion, a distalportion and a distal face proximate the distal end of the optical fiber;a layer of cladding radially surrounding the core from the core proximalportion to a designated point adjacent the core distal portion; a sleeveradially surrounding the cladding layer composed essentially of apredetermined type of material; and, a tip diffuser positioned at thedistal end of the optical fiber. The tip diffuser further includes: afirst substantially ring-shaped portion radially surrounding adesignated section of the core distal portion, where the first tipdiffuser portion includes light-scattering material therein whichfluoresces in a temperature dependent manner upon being stimulated bylight; and, a second tip diffuser portion terminating in a penetratingtip and being composed essentially of the sleeve type of material. Thefirst tip diffuser portion includes a first end attached to the distalend of the sleeve and a second end attached to the second tip diffuserportion. The second tip diffuser portion includes an end opposite thepenetrating tip attached to the first tip diffuser portion. The opticalfiber may also include a third substantially ring-shaped portionradially surrounding an upstream section of the core distal portionwhich is composed essentially of the sleeve type of material. The thirdtip diffuser portion includes a first end attached to the distal end ofthe sleeve and a second end attached to the first tip diffuser portion.The first tip diffuser portion is configured so that the second andthird tip diffuser portions may or may not be directly attached.

In a second exemplary embodiment of the invention, a diffuser tip for anoptical fiber of a laser device is disclosed, wherein the optical fiberincludes a core with a proximal portion and a distal portion. Thediffuser tip further includes: a first substantially ring-shaped portionradially surrounding a designated section of the core distal portion,where the first tip diffuser portion includes light-scattering materialtherein which fluoresces in a temperature dependent manner upon beingstimulated by light; a second portion radially surrounding a secondsection of the core distal portion and terminating in a penetrating tip,where the second tip diffuser portion is composed essentially of afluoropolymer material; and, a third substantially ring-shaped portionradially surrounding a third section of the core distal portion, wherethe third tip diffuser portion is composed essentially of thefluoropolymer material.

In accordance with a third embodiment of the present invention, a methodof making an improved diffuser in an optical fiber for use with a laserdevice is disclosed, wherein the optical fiber includes a core having aproximal portion, a distal portion, and a distal surface and a sleevecomposed essentially of a predetermined type of material radiallysurrounding the core from the proximal portion to the distal portion.The method includes the following steps: mixing a light-scatteringmaterial and the same type of material utilized for the sleeve into asubstantially homogeneous mixture; molding a first substantiallyring-shaped tip diffuser portion from the mixture sized to radiallysurround a designated section of the core distal portion; and, molding asecond tip diffuser portion from the same type of material utilized forthe sleeve to surround a second section of the core distal portion.Additionally, the method may include the steps of attaching the firstand second tip diffuser portions so as to have a common longitudinalaxis therethrough, forming a penetrating tip of predetermined geometryat one end of the second tip diffuser portion, and abrading an interiorsurface of the first diffuser portion prior to the attaching step.Further, the method may include the step of molding a thirdsubstantially ring-shaped tip diffuser portion from the same type ofmaterial utilized for the sleeve to surround an upstream section of thecore distal portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of a laser system utilized for performingmedical procedures which includes the optical fiber of the presentinvention;

FIG. 2 is an enlarged, partial sectional view of the optical fiberdepicted in FIG. 1, where the penetrating tip has not been formed;

FIG. 3 is an enlarged, partial sectional view of the optical fiberdepicted in FIGS. 1 and 2, where the penetrating tip has been formed;

FIG. 4 is an enlarged, sectional view of the slug in the optical fiberas depicted in FIGS. 2 and 3;

FIG. 5 is an enlarged, sectional view of a first alternative embodimentfor the slug depicted in FIGS. 2 and 3;

FIG. 6 is an enlarged, sectional view of a second alternative embodimentfor the slug depicted in FIGS. 2 and 3;

FIG. 7 is an enlarged, sectional view of the slug depicted in FIG. 4including a feature formed in one end thereof for interfacing with anassembly tooling spaced therefrom;

FIG. 8 is an enlarged, sectional view of the slug depicted in FIG. 4including an alternative feature formed in one end thereof forinterfacing with an assembly tooling spaced therefrom;

FIG. 9 is an enlarged, partial sectional view of a first alternativeembodiment for the optical fiber depicted in FIGS. 1-3, where a tipdiffuser is in a detached position and the penetrating tip has not beenformed;

FIG. 10 is an enlarged, partial sectional view of the optical fiberdepicted in FIG. 9, where the tip diffuser is in the attached positionand the penetrating tip has been formed;

FIG. 11 is an enlarged, partial sectional view of a second alternativeembodiment for the optical fiber depicted in FIGS. 1-3, where a tipdiffuser is in the attached position and the penetrating tip has beenformed;

FIG. 12 is an enlarged, partial sectional view of a fourth alternativeembodiment for the optical fiber depicted in FIGS. 1-3, where a tipdiffuser including a ring-shaped portion made of light scatteringmaterial and the sleeve material is in the attached position and thepenetrating tip has been formed; and,

FIG. 13 is an enlarged, partial sectional view of a third alternativeembodiment for the optical fiber depicted in FIGS. 1-3, where a tipdiffuser incorporating a ring-shaped slug made of light scatteringmaterial is in the attached position and the penetrating tip has beenformed.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings in detail, wherein identical numeralsindicate the same elements throughout the figures, FIG. 1 depictsschematically a medical instrument 10 for diffusing light from anoptical fiber 12. Medical instrument 10 includes a source of lightenergy 14, which preferably is a laser. Optical fiber 12 connects intolight energy source 14 through the intermediary of a connector 16 whichis attached to a connection port 18 leading to a diffuser portion 20 ofoptical fiber 12. A typical connector and connection port of this kindwhich can be utilized for medical instrument 10 is the Optima laserwhich is sold by Ethicon Endo-Surgery in Cincinnati, Ohio. It will beappreciated that optical fiber 12 with the attached connector 16 may beprovided and sold separately from light energy source 14 as an opticfiber assembly.

More specifically, optical fiber 12 includes a proximal end 22 incommunication with light energy source 14 which transmits light to adistal end 24 including diffuser portion 20 that is utilized to diffuselight at a treatment site. Optical fiber 12 further includes a pluralityof assembled components which enable it to function in an intendedmanner, as in the case for the treatment of BPH. It will be seen fromFIGS. 2 and 3 that optical fiber 12 includes a core 26 which extendssubstantially through the center of optical fiber 12. Core 26, which istypically made of silica glass, has a proximal portion 28 incommunication with light energy source 14 and functions to transmitlight to a distal portion 30 that is located within diffuser portion 20.It will be understood that distal portion 30 includes a distal face 32.In this way, diffuser portion 20 functions to diffuse the light energyreceived from proximal portion 28. A layer of cladding 34 is preferablyprovided so as to radially surround core 26 from core proximal portion28 to a point adjacent to core distal portion 30. Cladding layer 34,which protects core 26 by imparting a mechanical support thereto,preferably has an index of refraction lower than that of the materialused to create core 26 so as to contain or block the light transmittedthrough optical fiber 12 from emerging radially from core 26.

Optical fiber 12 further includes a layer 36 of optical couplingmaterial which preferably radially surrounds at least a portion 38 ofcore distal portion 30 and possibly a portion of cladding layer 34.Exemplary optical coupling materials include: XE5844 Silicone, which ismade by General Electric Company; UV50 Adhesive, available fromChemence, Incorporated in Alpharetta, Ga.; and, 144-M medical adhesive,which is available from Dymax of Torrington, Conn. Optical couplinglayer 36 preferably has a higher index of refraction than core 26 sothat light exits core 26.

In the embodiment of the invention depicted in FIGS. 2 and 3, a slug 40positioned adjacent distal face 32 functions to scatter light backthrough core 26 and thereby raise the intensity of the light in diffuserportion 20. Slug 40, as discussed previously herein, has heretofore beencomposed essentially of a light-scattering material and an adhesive.Typical scattering materials have included aluminum oxide, titaniumdioxide, and diamond power, but alexandrite has been found to be apreferred material. This is because alexandrite not only is able toperform the light-scattering function, but it also exhibits atemperature dependent optical fluorescence decay rate upon beingstimulated by light of a predetermined wavelength. Accordingly, thealexandrite is able to emit a light signal back through core 26 fromwhich a temperature for diffuser portion 20 can be determined andcontrolled. It will be appreciated that the adhesive generally mixedwith the light-scattering material may or may not be the same as foroptical coupling layer 36.

It will be noted that optical fiber 12 also preferably includes a sleeve42 which radially surrounds optical coupling layer 36 and slug 40. Abuffer layer 43 is preferably positioned radially between sleeve 42 andcladding layer 34 upstream of and perhaps into diffuser portion 20.Sleeve 42 is composed essentially of a predetermined type of materialwhich preferably has an index of refraction higher than the materialused for optical coupling layer 36. Further, such material is preferablyflexible, is non-absorbent of laser energy in the wavelengths ofinterest, has a high melt temperature, and is optically diffusing. Apreferred material for sleeve 42 having the desired characteristics isperfluoroalkoxy (PFA) impregnated with barium sulfate, where the bariumsulfate particles assist in scattering light energy evenly outward tothe tissue at the treatment site. Other materials optically transparentto the appropriate wavelengths may be used to construct sleeve 42,including Ethylenetetraflouroethylene (ETFE) and other types offlouropolymers.

Turning back to slug 40, the present invention involves molding thealexandrite (or other light-scattering material having similartemperature dependent properties when stimulated by light) withsubstantially the same type of material utilized for sleeve 42. It willbe appreciated that a preferred concentration of the alexandrite in slug40 exists and is dependent upon the configuration and composition ofslug 40. In the case where slug 40 is a substantially homogeneousmixture of alexandrite and perfluoroalkoxy with approximately 10% bariumsulfate (see FIG. 4), the preferred concentration of alexandrite thereinis in a range of approximately 25-75% by weight.

With respect to the overall configuration of slug 40, it will be seenthat slug 40 preferably radially surrounds a portion 44 of core distalportion 30. Accordingly, a feature 46 is preferably incorporated into afirst end 48 of slug 40 for centering slug 40 onto core distal portion30. Further, slug 40 preferably includes a negative feature 50 formedinto a second end 52 thereof for interfacing with a positive assemblytooling 54 (see FIG. 7). Alternatively, a positive feature 56 ispreferably formed into second end 52 thereof for interfacing with anegative assembly tooling 58 (see FIG. 8). In either case, insertion ofslug 40 onto core distal portion 30 is facilitated. It will beappreciated, however, that differing the tooling feature from thecentering feature assists in preventing misassembly. Because slug 40essentially consists of the same type of material as that utilized forsleeve 42, and an interior surface 60 of sleeve 42 is preferably abradedto include grooves 62 or other variable surface characteristics, slug 40achieves a mechanical connection with sleeve 42 via a physical bondingduring the formation of a penetrating tip 64 on sleeve 42. Inparticular, the material of slug 40 melts and bonds with the material ofsleeve 42 since they have substantially the same melting points.

It will also be seen that additional embodiments of slug 40 are depictedin FIGS. 5 and 6 which differ from the substantially homogeneous mixturerepresented in FIG. 4. In FIG. 5, slug 66 includes a first portion 68consisting essentially of a light-scattering material (e.g., alexandriteor any other material having similar properties and characteristics)which is positioned adjacent to core distal face 32. In addition, slug66 includes a second portion 70 consisting essentially of the same typeof material utilized for sleeve 42 (e.g., perfluoroalkoxy with bariumsulfate particles or any other material having similar properties andcharacteristics). Second slug portion 70 is preferably molded so as tobe positioned around first slug portion 68 and portion 44 of core distalportion 30.

With respect to FIG. 6, it will be seen that slug 72 therein includes afirst portion 74 consisting essentially of a substantially homogeneousmixture of a light-scattering material and material of the same typeutilized for sleeve 42 (e.g., alexandrite and perfluoroalkoxy withbarium sulfate particles or other compositions having similar propertiesand characteristics), where first slug portion 74 is positioned adjacentto core distal face 32. A second portion 76 of slug 72 consistingessentially of the same type of material utilized for sleeve 42 (e.g.,perfluoroalkoxy with barium sulfate particles or any other materialhaving similar properties and characteristics) is molded so as to bepositioned around first slug portion 74 and portion 44 of core distalportion 30.

In a second embodiment of the optical fiber (identified generally byreference numeral 78), it will be seen from FIGS. 9 and 10 that slug 40from FIGS. 2 and 3 has been eliminated. Further, while core 26, claddinglayer 34, and buffer layer 43 remain unchanged, a sleeve 80 is providedwhich radially surrounds cladding layer 34 but not core distal portion30. Accordingly, a tip diffuser 82 is provided which preferablysurrounds core distal portion 30 and core distal face 32. In this way,the area of core 26 which receives the most treatment light alsoreceives the most marker light excitation. Thus, the temperaturemeasurement is weighted more closely to the tissue being treated.

As discussed previously herein with respect to slug 40, tip diffuser 82preferably includes a light-scattering material (e.g., alexandrite orany other material having similar properties and characteristics) moldedwith substantially the same type of material utilized for sleeve 80. Tipdiffuser 82 includes a first end 84 which is positioned adjacent adistal end 86 of sleeve 80 and a second end 88 which preferably isformed into a penetrating tip 90. It will be appreciated that first end84 of tip diffuser 82 is preferably attached to sleeve distal end 86,such as by heat staking or welding.

A layer 92 of optical coupling material is preferably located betweencore distal portion 30 and tip diffuser 82. As seen in FIGS. 9 and 10,an interior surface 94 of tip diffuser 82 is preferably abraded toinclude grooves 96 or other variable surface characteristics so that amechanical connection with optical coupling layer 92 is achieved and thedisadvantage of index of refraction is overcome.

It will be appreciated that tip diffuser 82 is preferably asubstantially homogeneous mixture of the light-scattering material andthe material utilized for sleeve 80. Further, a preferred concentrationof alexandrite in tip diffuser 82 exists and is dependent upon theconfiguration and composition of tip diffuser 82. In the case where tipdiffuser 82 is a substantially homogeneous mixture of alexandrite andperfluoroalkoxy with approximately 10% barium sulfate, the preferredconcentration of alexandrite therein is in a range of approximately25-75%. It will be appreciated, however, that such concentration ofalexandrite is likely to be less for tip diffuser 82 than for slug 40described previously herein due to their respective orientations withregard to core distal portion 30.

FIG. 11 depicts a third embodiment of an optical fiber identifiedgenerally by reference numeral 98. Optical fiber 98 likewise includescore 26, buffer layer 43, and sleeve 80 as shown in FIGS. 9 and 10. Anew tip diffuser 100 is utilized with optical fiber 98 which preferablyis formed as a solid rod having a first end 102 positioned adjacentdistal end 86 of sleeve 80 and a second end 104 which preferablyterminates in a penetrating tip 106. It will be appreciated that firstend 102 of tip diffuser 100 is preferably attached to sleeve distal end86, such as by heat staking or welding.

Contrary to tip diffuser 82 of optical fiber 78, tip diffuser 100 has asmaller portion 107 hollowed therefrom at first end 102 so that only aportion 108 of core distal portion 30 extends therein. It will be notedthat a cladding layer 110 radially surrounding core 26 extends into coredistal portion 30 to core distal face 32. A layer 112 of opticalcoupling material is then preferably located between core distal face 32and tip diffuser 100 to facilitate light emission from core distalportion 30. This particular configuration, where cladding layer 110extends further on core 26, is effective for enhancing the flexibilityof core distal portion 30 and thus rendering optical fiber 98 morecompatible with certain flexible endoscopes.

Tip diffuser 100 preferably includes a light-scattering material (e.g.,alexandrite or any other material having similar properties andcharacteristics) molded with substantially the same type of materialutilized for sleeve 80. Once again, it will be appreciated that tipdiffuser 100 is preferably a substantially homogeneous mixture of thelight-scattering material and the material utilized for sleeve 80.Further, a preferred concentration of alexandrite in tip diffuser 100exists and is dependent upon the configuration and composition thereof.When tip diffuser 100 is a substantially homogeneous mixture ofalexandrite and perfluoroalkoxy with approximately 10% barium sulfate,the preferred concentration of alexandrite therein is in a range ofapproximately 25-75%. It will be appreciated, however, that suchconcentration of alexandrite is likely to be less for tip diffuser 100than for slug 40 described previously herein due to their respectiveorientations with regard to core distal portion 30.

A fourth embodiment of an optical fiber 114 is depicted in FIG. 12. Asseen therein, optical fiber 114 is configured to have core 26, claddinglayer 34, buffer layer 43, and sleeve 80 as described above with respectto FIGS. 9 and 10. Another tip diffuser 116 is provided which preferablysurrounds core distal portion 30 and core distal face 32. Further, tipdiffuser 116 includes a first end 118 positioned adjacent distal end 86of sleeve 80 and a second end 120 which preferably terminates in apenetrating tip 122. It will be appreciated that first end 118 of tipdiffuser 116 is preferably attached to sleeve distal end 86, such as byheat staking or welding. It will be appreciated that an optical couplinglayer 123 is shown as being provided between core distal portion 30 andtip diffuser 116.

More specifically, as seen in the upper portion of FIG. 12, tip diffuser116 preferably includes a first substantially ring-shaped portion 124which is sized to fit radially around a designated section 126 of coredistal portion 30. Accordingly, first tip diffuser portion 124 ispositioned axially at a middle section of core distal portion 30) alonga longitudinal axis 133 through core distal portion 30. It is preferredin this embodiment that core distal portion 30 extend at least to amidpoint in tip diffuser 116 so that the temperature sensing ability offirst tip diffuser portion 124 is enhanced by receiving the strongestlight. In this configuration, first diffuser tip portion 124 includes afirst end 127 (same as first end 118 of tip diffuser 116) which isattached to sleeve distal end 86 (e.g., by heat staking or welding) anda second end 128.

First diffuser tip portion 124 preferably consists of an exemplarylight-scattering material (e.g., alexandrite or some other materialexhibiting similar properties and characteristics) or a substantiallyhomogeneous mixture of such light-scattering material and the materialutilized for sleeve 80 (e.g., perfluoroalkoxy with barium sulfateparticles or some material exhibiting similar properties andcharacteristics). Of course, a preferred concentration of alexandrite infirst tip diffuser portion 124 exists and is dependent upon theconfiguration and composition thereof. When first tip diffuser portion124 is a substantially homogeneous mixture of alexandrite andperfluoroalkoxy with approximately 10% barium sulfate, the preferredconcentration of alexandrite therein is in a range of approximately25-75%. It will be appreciated, however, that such concentration ofalexandrite is likely to be less for first tip diffuser portion 124 thanfor slug 40 described previously herein due to their respectiveorientations with regard to core distal portion 30.

Tip diffuser 116 further includes a second portion 130 which preferablyradially surrounds a second section 132 of core distal portion 30 andterminates in penetrating tip 122. Second tip diffuser portion 130,which preferably is composed essentially of the same material utilizedfor sleeve 80, includes an end 134 opposite penetrating tip 122 which isattached to second end 128 of first diffuser tip portion 124 (e.g., byheat staking or welding).

As seen in a bottom portion of FIG. 12, tip diffuser 116 may include athird substantially ring-shaped portion 136 which is sized to fitradially around an upstream or third section 138 of core distal portion30. Third tip diffuser portion 136, which preferably consistsessentially of the same type of material as sleeve 80, is locatedadjacent sleeve distal end 86A and includes a first end 140 (same asdiffuser tip first end 118) and a second end 142 located oppositethereto. According, first end 140 of third diffuser section is attachedto sleeve distal end 86A (e.g., by means of heat staking or welding) andsecond end 142 thereof is attached to first end 127 of first tipdiffuser portion 124.

In yet another alternative optical fiber embodiment (represented byreference numeral 143) depicted in FIG. 13, it will be seen that a tipdiffuser 144 includes a first tip diffuser portion 146, a seconddiffuser tip portion 148 and a third tip diffuser portion 150. Asindicated above with respect to tip diffuser 116, third diffuser tipportion 150 is substantially ring-shaped, preferably consistsessentially of the same type of material as sleeve 80, and is sized tofit radially around a third or upstream section 152 of core distalportion 30. Third diffuser tip portion 150 is located adjacent sleevedistal end 86 and includes a first end 154 and a second end 156 locatedopposite thereto.

Similarly, second diffuser tip portion 148 radially surrounds a secondsection 158 of core distal portion 30 and terminates in penetrating tip160. Second tip diffuser portion 148, which preferably is composedessentially of the same material utilized for sleeve 80, includes an end162 opposite penetrating tip 160 which is attached to second end 156 ofthird diffuser tip portion 146 (e.g., by heat staking or welding).

It will be noted that first tip diffuser portion 146 is preferably sizedand configured so that a first end 164 and at least a portion thereof isreceived within, or otherwise mated with, a feature 166 formed in amiddle section 168 of third tip diffuser portion second end 156. Asimilar feature 170 may be formed in a middle section 172 of second tipdiffuser portion end 162 so that a second end 174 and at least a portionof first tip diffuser portion 146 is received therein or otherwise matedtherewith. In particular, while features 166 and 170 are depicted as afemale type, such features could alternatively have a male configurationwhich extends into complementary female portions formed in first andsecond ends 164 and 174, respectively, of first tip diffuser portion146. In either case, first tip diffuser portion 146 will preferablyradially surround a middle section 176 of core distal portion 30.

In conjunction with the optical fiber embodiments described herein, oneimprovement related thereto is the method of making and assembling suchoptical fibers. With respect to optical fiber 12, a method of makingsuch optical fiber 12 includes an initial step of providing sleeve 42radially around core 26 so that a length 178 of the open sleeve thereofextends beyond core distal face 32 a predetermined amount. The next stepinvolves molding the light-scattering material with a material similarto that utilized for sleeve 42 to form slug 40, where thelight-scattering material fluoresces in a temperature dependent mannerupon being stimulated by light. Thereafter, slug 40 is inserted intoopen sleeve length 178 so as to be positioned adjacent core distal face32. Open sleeve length 178 is then shaped into penetrating tip 64 havinga predetermined geometry. It will be appreciated that slug 40 is alsophysically bonded to sleeve 42 during the tip shaping step. Also, it ispreferred that optical coupling layer 36 be provided between core distalportion 30 and sleeve 42.

It will be understood with regard to the physical features of slug 40that the method further may include the step of molding feature 46 atfirst end 48 of slug 40 for centering slug 40 with core distal portion30. Another step may include the molding of negative feature 50 orpositive feature 56 on second end 52 of slug 40 to facilitate placementof slug 40 on a corresponding assembly tooling 54 or 58, respectively,for the inserting step.

With respect to the materials utilized for slug 40, a preferred step isoptimizing slug 40 with a predetermined concentration of thelight-scattering material to the sleeve-type material utilizedtherewith. This can be different depending on the configuration andcomposition of slug 40. In a first instance, this involves the step ofmixing the light-scattering material and the same type of material asutilized for sleeve 42 into a substantially homogeneous mixture prior tothe molding step. For slug 66, the molding step further includes thesteps of preloading the light-scattering material in a mold andcompression molding the same type of material as utilized for sleeve 42directly over and through the light-scattering material. The moldingstep for slug 72 further includes the following steps: mixing thelight-scattering material and the same type of material as utilized forsleeve 42 into a substantially homogeneous mixture; molding firstportion 74 of slug 72 with the mixture; and, molding second portion 76of slug 72 from the same type of material as utilized for sleeve 42 soas to surround all but one side (that used to interface core distal face32) of first slug portion 74.

Regarding optical fibers 78, 98, 114 and 143 shown in FIGS. 10, 11, 12,and 13 respectively, it will be understood that the process of makingthem involves the step of molding the light-scattering material with thesame type of material utilized for sleeve 80 into at least a portion oftip diffusers 82, 100, 116, and 144, respectively, having apredetermined length and geometry. Thereafter, the respective tipdiffuser 82, 100, 116 or 144 is inserted over at least a portion of coredistal portion 30. The tip diffuser 82, 100, 116 or 144 is then attachedat a first end 84, 102, 118, or 154, respectively, to distal end 86 ofsleeve 80. Of course, the process also involves the step of formingpenetrating tip 90, 106, 122 and 160 at second end 88, 104, 120, and155, respectively, for each tip diffuser 82, 100, 116, and 144. Theformation of penetrating tips 90, 106, 122 and 160 may occur prior to orafter the inserting step described above.

It will be noted with respect to optical fibers 78, 114 and 143 that themethod preferably includes the step of providing layers 92, 123, and157, respectively, of optical coupling material between core distalportion 30 and tip diffusers 82, 116, and 143. In order to provide adesired physical or mechanical connection between optical couplinglayers 92, 123, and 157 and interior surfaces 94, 125, and 159 of tipdiffusers 82, 116, and 143, respectively, interior surfaces 94, 125, and159 are preferably abraded prior to the inserting step. For opticalfibers 78, 114, and 143, it will be seen that tip diffusers 82, 116, and144 thereof extend around substantially all of core distal portion 30,whereas tip diffuser 100 of optical fiber 98 extends around only a smallportion 108 of core distal portion 30.

With regard to the composition of tip diffusers 82 and 100, the processmay further include the steps of mixing the light-scattering materialand the same type of material utilized for sleeve 80 into asubstantially homogeneous mixture and molding the mixture into such tipdiffusers 82 and 100 having the predetermined length and geometry.

Regarding optical fibers 114 and 143, the process preferably includesthe following additional steps: mixing the light-scattering material andthe same type of material utilized for sleeve 80 into a substantiallyhomogeneous mixture; molding first tip diffuser portions 124 and 146from the mixture into a ring shape sized to radially surround sections126 and 176 of core distal portion 30; and, molding second tip diffuserportions 130 and 148 from the same type of material utilized for sleeve80 to surround sections 132 and 158. Additionally, such processpreferably includes the step of attaching the respective first tipdiffuser portions 124 and 146 and second tip diffuser portions 130 and148 so as to have a common longitudinal axis 133 and 161 therethrough.Further steps may include forming penetrating tips 122 and 160 ofpredetermined geometry in second tip diffuser portions 130 and 148 andabrading interior surfaces 125 and 159 of tip diffusers 116 and 144.

Optionally, the process may include the step of molding third tipdiffuser portions 138 and 150 from the same type of material utilizedfor sleeve 80 into a ring shape sized to radially surround sections 138and 152 of core distal portion 30.

With respect to optical fiber 116, it will be appreciated that first tipdiffuser portion 124 is preferably configured so that the method thereofincludes attaching first end 126 to sleeve distal end 86 or to secondend 142 of third tip diffuser portion 136 by heat staking or welding. Ineither case, second end 128 thereof is attached to non-penetrating tipend 134 of second tip diffuser portion 130 and 148, respectively.

With respect to optical fiber 143, the manner of attaching first tipdiffuser portion 146 involves the steps of forming feature 166 in secondend 156 of third tip diffuser portion 150 and/or forming feature 170 inend 162 of second tip diffuser portion 148. In this way, first tipdiffuser portion 146 is mated with second and/or third tip diffuserportions 148 and 150.

Having shown and described the preferred embodiment of the presentinvention, further adaptations of optical fibers 12, 78, 98, and 114,including slugs 40, 66 and 72 and/or sleeves 42 and 80 thereof, as wellas the methods making and assembling such optical fibers, can beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the invention.

1. An optical fiber for use with a laser device including a source oflight energy, said optical fiber having a proximal end in communicationwith the light source and a distal end positionable at a treatment site,said optical fiber comprising: (a) a core having a proximal portion, adistal portion and a distal face proximate said distal end of saidoptical fiber; (b) a layer of cladding radially surrounding said corefrom said core proximal portion to a designated point adjacent said coredistal portion; (c) a sleeve radially surrounding said cladding layercomposed essentially of a predetermined type of material; and, (d) a tipdiffuser positioned at said distal end of said optical fiber, said tipdiffuser further comprising: (1) a first substantially ring-shapedportion radially surrounding a designated section of said core distalportion, said first tip diffuser portion including light-scatteringmaterial therein which fluoresces in a temperature dependent manner uponbeing stimulated by light; and, (2) a second portion terminating in apenetrating tip and being composed essentially of said sleeve type ofmaterial.
 2. The optical fiber of claim 1, wherein said first tipdiffuser portion is positioned axially at a middle section of said coredistal portion.
 3. The optical fiber of claim 1, wherein said coredistal portion extends past a midpoint of said first tip diffuserportion.
 4. The optical fiber of claim 1, further comprising a layer ofoptical coupling material located between said core distal portion andsaid first tip diffuser portion.
 5. The optical fiber of claim 1,wherein said light-scattering material exhibits a temperature dependentoptical fluorescence decay rate.
 6. The optical fiber of claim 5,wherein said light-scattering material of said tip diffuser isalexandrite.
 7. The optical fiber of claim 1, wherein said sleeve typeof material is a fluoropolymer.
 8. The optical fiber of claim 7, whereinsaid sleeve material is perfluoroalkoxy impregnated with barium sulfateparticles.
 9. The optical fiber of claim 1, said first tip diffuserportion further comprising a first end attached to said distal end ofsaid sleeve and a second end attached to said second tip diffuserportion.
 10. The optical fiber of claim 1, said second tip diffuserportion further comprising an end opposite said penetrating tip attachedto said first tip diffuser portion.
 11. The optical fiber of claim 1,further comprising a third substantially ring-shaped portion radiallysurrounding an upstream section of said core distal portion, said thirdtip diffuser portion being composed essentially of said sleeve typematerial;
 12. The optical fiber of claim 1, said third tip diffuserportion further comprising a first end attached to said distal end ofsaid sleeve and a second end attached to said first tip diffuserportion.
 13. The optical fiber of claim 12, said third diffuser portionfurther comprising a feature formed in said second end for mating withsaid first tip diffuser portion.
 14. The optical fiber of claim 1, saidsecond tip diffuser portion further comprising a feature formed in afirst end opposite said penetrating tip for mating with said firstdiffuser tip portion.
 15. The optical fiber of claim 1, wherein aconcentration of said light-scattering material to said sleeve type ofmaterial in said tip diffuser is in a range of approximately 25-75%. 16.The optical fiber of claim 12, wherein said second and third tipdiffuser portions are a substantially homogeneous mixture of saidlight-scattering material and said sleeve type of material.
 17. Adiffuser tip for an optical fiber of a laser device, wherein saidoptical fiber includes a core with a proximal portion and a distalportion, said diffuser tip comprising: (a) a first substantiallyring-shaped portion radially surrounding a designated section of saidcore distal portion, said first tip diffuser portion includinglight-scattering material therein which fluoresces in a temperaturedependent manner upon being stimulated by light; (b) a second portionradially surrounding a second section of said core distal portion andterminating in a penetrating tip, said second tip diffuser portion beingcomposed essentially of a fluoropolymer material; and, (c) a thirdsubstantially ring-shaped portion radially surrounding a third sectionof said core distal portion, said third tip diffuser portion beingcomposed essentially of said fluoropolymer material;
 18. A method ofmaking an improved diffuser in an optical fiber for use with a laserdevice, wherein said optical fiber includes a core having a proximalportion, a distal portion, and a distal surface and a sleeve composedessentially of a predetermined type of material radially surroundingsaid core from said proximal portion to said distal portion, said methodcomprising the following steps: (a) mixing a light-scattering materialand the same type of material utilized for said sleeve into asubstantially homogeneous mixture; (b) molding a first substantiallyring-shaped tip diffuser portion from said mixture sized to radiallysurround a designated section of said core distal portion; and, (c)molding a second tip diffuser portion from the same type of materialutilized for said sleeve to surround a second section of said coredistal portion.
 19. The method of claim 18, further comprising the stepof attaching said first and second tip diffuser portions so as to have acommon longitudinal axis therethrough.
 20. The method of claim 18,further comprising the step of forming a penetrating tip ofpredetermined geometry at one end of said second tip diffuser portion.21. The method of claim 19, further comprising the step of abrading aninterior surface of said first tip diffuser portion prior to saidattaching step.
 22. The method of claim 18, further comprising the stepof molding a third substantially ring-shaped tip diffuser portion fromthe same type of material utilized for said sleeve to surround anupstream section of said core distal portion.
 23. The method of claim22, further comprising the following steps: (a) forming a feature in oneend of said third diffuser tip portion; and, (b) mating said first tipdiffuser portion with said third diffuser tip portion.
 24. The method ofclaim 18, further comprising the following steps: (a) forming a featurein one end of said second tip diffuser portion; and, (b) mating saidsecond tip diffuser portion with said first tip diffuser portion.